Process for the preparation of aromatic urethanes

Abstract

An aromatic urethane (e.g., methyl naphthyl urethane) is prepared by reacting an aromatic hydroxy compound, such as alpha-naphthol, with an aliphatic urethane, such as dimethyl urethane, in the presence of a catalyst consisting of a Lewis acid.

What we claim is: 
     
       1. The process of preparing an aromatic urethane having the formula: ##STR2## wherein Ar is a phenyl or naphthyl group and R is alkyl, which consists in reacting the corresponding alkyl carbamate ester with a phenol or naphthol corresponding to Ar, in the liquid phase and in the presence of a catalyst consisting of AlCl 3  or ZnCl 2  under subatmospheric conditions in the temperature range of 100° to 300° C. 
     
     
       2. A process for the preparation of an aromatic urethane as claimed in claim 1, wherein the reaction is effected in the temperature range between 150° and 250° C. 
     
     
       3. A process for the preparation of an aromatic urethane as claimed in claim 1, wherein the reaction is effected at a phenol or naphthol/alkyl carbamate ester molar ratio between 10:1 and 1:10. 
     
     
       4. A process for the preparation of naphthyl methylcarbamate, which consists in reacting alpha-naphthol or betanaphthol and methyl methylcarbamate in the presence of a catalyst consisting of AlCl 3  or ZnCl 2  under subatmospheric conditions at a temperature in the range of 150° to 170° C.